converting an 8 3/4 to the correct sure-grip

I like the idea of going at it as several suggest with just putting in my 8 -3/4 as is for now to enjoy hanging up the new complete spring system I got from Springs n things without changing out the diff for now. As easy as that is (along with getting the driveshaft correct) I wonder if there is any reason to open up the box to inspect it's overall condition first? From all appearances the case and axles don't look like they've been beat around but my mopar buddy insists "just hang it and run it around" to listen for noise is what most do. I love the nuts and bolts aspect of this part of my restoration and understand that popping in the posi later is simple once everything is hung. I intend for this to be highway gear perfect show driver.